The use of cationic polymers to enhance deposition of particles has been disclosed, for example, by applicants. In several of applicants' co-pending applications (e.g., U.S. Ser. No. 10/997,179 to Tsaur et al.; U.S. Ser. No. 10/997,180 to Patel et al.; U.S. Ser. No. 11/043,509 to Polonka et al.), for example, applicants disclose compositions comprising cationic polymer as part of a deposition system for delivering particles providing optical benefits. In these applications, however, cationic polymers interact with anionic surfactant to form a precipitate or coacervate which enhances deposition of particles.
In co-pending U.S. Ser. Nos. 11/370,109 and 11/370,267, both to Polonka et al., the “deposition system” (cationic polymer/anionic surfactant) forms individually on particles to be deposited. The thus “coated” particles interact with air to form a foam lather structure and particles are deposited predominantly from lather in use. The individual deposition system chemistry still, however, is dependent on anionic surfactant interacting with cationic particles. None of the above references disclose the novel modified polymers of the invention or the use of these hydrophobically modified cationic polymers to interact directly with benefit agent (e.g., benefit agent particles), without need of anionic surfactant as part of deposition system, to enhance benefit agent deposition. Benefit agents with which hydrophobically modified cationics can react can, in principle, include emulsions of silicones or oils to the extent the emulsion is naturally negatively charged, it will interact with the modified cationic to enhance deposition.
U.S. Application No. 2004/0223993 to Clapp et al. disclose direct hydrophobic modification of particles, but not the hydrophobically modified cationic polymers of the invention. U.S. Pat. No. 6,780,826 to Zhang discloses deposition of particles based on particle geometry.
In a reference entitled “Effects of low-level substitution on conditioning properties of cationic cellulosic polymers in shampoo systems”, Journal of Cosmetic Science, volume 55, pages S195-S205 (2004), T. V. Drovetskaya et al. disclose quaternized hydroxyethylcellulose polymers having hydrophobic character due to grafting of dimethyl dodecyl ammonium groups onto the cellulose backbone. The product is known commercially as Polymer SL®. Cationic substitution is achieved with trimethyl ammonium grafts.
In Polymer SL®, the degree of cationic substitution is fixed as 0.2, meaning that one in five anhydroglucose units contains a quaternized graft. This level of modified cation corresponds to 1% nitrogen. Since the repeat unit molecular weight for a cellulose backbone with this level of cationic grafts is about 300, this material has a cationic charge density of 0.7 milli-equivalents per gram. Polymers of the subject invention have charge density ≧2 meq/g, preferably ≧2.5 meq/g, more preferably ≧4 meq/g.
Zhao et al. of Chinese Academy of Sciences published a paper entitled “Synthesis and Flocculation Properties of Poly (dialkyl dimethyl ammonium chloride-vinyl trimethoxysilane) and poly (diallyl dimethyl ammonium chloride-acrylamide-vinyl trimethoxysilane) in Journal of Applied Polymer Sciences, Volume 84, pp 335-342 (2002).
Zhao discloses the use of polymers as flocculants for water treatment. Polymers use relatively low levels of hydrophobe (less than 10 mole % compared to those of invention which we use 10 mol % and greater) since higher levels are said to lead to insolubility.